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Biomedical subjects

Y Iida

Publications and source records attributed to Y Iida.

At least 343 records · Page 19Linked to original sources
PubMed1981

Analysis of alveolar PCO2 control during the menstrual cycle.

We attempted to analyze how PACO2 is regulated during progesterone-induced hyperventilation in the luteal phase. A model for the CO2 control loop was constructed, in which the function of the CO2 exchange system was described as PACO2 = 0.863 x VCO2/VA (gain H = dPACO2/dVA) and that of the CO2 sensing system as VA = S (PACO2 - B). Using this model, we estimated (1) the primary increase in VA (delta VA (op)) produced by progesterone stimulation and (2) the effectiveness (E) of the loop to regulate PACO2, defined as delta PACO2 (op)/delta PACO2 (cl) in which op signifies open-loop and cl, closed-loop. These respiratory variables were investigated throughout the menstrual cycle in 8 healthy women. During the luteal phase, on average, VA increased by 9.4% and PACO2, B and H decreased by 0.33 kPa (2.5 mm Hg), 0.47 kPa (3.5 mm Hg) and 13.6%, respectively, while S and VCO2 did not change significantly. Delta VA (op) increased progressively on successive days of the luteal phase while E remained unchanged at a value of 7.9, thus there was a progressive decrease in PACO2. The decrease in H was considered to lessen delta PACO2 (op) and so reduce the final deviation of PACO2 (delta PACO2 (cl) during the luteal phase. The decrease in B was found to be dependent on delta VA (op).

Adult↗
PubMed1981

Characterization of triton-solubilized TSH receptors from human thyroid plasma membranes.

The TSH receptor from human thyroid plasma membranes has been solubilized in 10 mM Tris/HCl, 50 mM NaCl, pH 7.4 containing 0.5% triton X-100. Binding of [125I]TSH to the soluble receptor showed rapid and reversible kinetics and reached a maximum within 30 min at 37 degrees C, by 1 h at 25 degrees C and by 24 h 4 degrees C. Optimal pH was 7.4. The soluble receptor retained specificity with cross-reactivity only to crude hCG (0.03%). Scatchard plots were curvilinear indicating the presence of at least two binding sites. The high affinity site showed an affinity content of 1.1 X 10(9) M-1 with binding capacity of 1.3 X 10(-10) M/mg protein. TSH-binding inhibitor immunoglobulins from patients with Graves' disease inhibited [125I]TSH binding to the soluble receptor in a dose-dependent manner. NaCl inhibited the TSh binding and this was ascribed to the decrease in the receptor capacity. Trypsin, neuraminidase and phospholipase C treatment of the solubilized receptor had no effect on TSH binding. The apparent molecular weight of the receptor, determined by gel filtration of Sepharose 6B, was approximately 300 000.

Cell Membrane↗